Hair bleaching, is the practice of lightening the hair color mainly for cosmetic purposes using bleaching agents. Bleaching can be done alone, combined with a toner, or as a step for further hair coloring. The most common commercial bleaching agents in use are hydrogen peroxide and persulfate salts, but historically other agents such as sulfuric acid, wood ash, lye and hypochlorite bleach were used. Hair can also become bleached unintentionally, such as through sun exposure.
During the early years of the Roman Empire, blond hair was associated with prostitutes. [1] The preference changed to bleaching the hair blond when Greek culture, which practiced bleaching, reached Rome, and was reinforced when the legions that conquered Gaul returned with blond slaves. [2] Sherrow also states that Roman women tried to lighten their hair, but the substances often caused hair loss, so they resorted to wigs made from the captives' hair. [3] The bleaching agent used by the Roman women was composed of a solution of ashes from burnt nuts or plants. [4]
Diodorus Siculus, a 1st century BC Greek historian, described in detail how Celtic people bleached their hair: "Their aspect is terrifying... They are very tall in stature, with rippling muscles under clear white skin. Their hair is blond, but not naturally so: they bleach it, to this day, artificially, washing it in lime and combing it back from their foreheads. They look like wood-demons, their hair thick and shaggy like a horse's mane. Some of them are clean-shaven, but others—especially those of high rank—shave their cheeks but leave a moustache that covers the whole mouth...". [5] [6]
During the medieval period, Spanish women preferred to dye their hair black, yet by the time of the Renaissance in the 16th century the fashion (imported from Italy) was to bleach their hair blond or dye it red. [7] Between the Renaissance and the Enlightenment, a number of dangerous hair bleaching methods remained widely practiced, including the use of sulfuric acid, which was an accepted form of hair coloring around the 1600s, and laying out in the sun with hair covered in lye a century later. [4]
In Sir Hugh Plat's 1602 work Delightes for Ladies the use of oil of vitriol (sulfuric acid) to bleach black hair to chestnut is described as: "Take one part of lead calcined with Sulphur, and one part of quicklime: temper them somewhat thin with water: lay it upon the hair, chafing it well in, and let it dry one quarter of an hour or thereasbouts; the wash the same off with fair water divers times: and lastly with sope and water, and it will be a very natural hair-colour. The longer it lyeth upon the haire, the browner it groweth, This coloureth not the flesh at all, and yet it lasteth very long in the hair." [8]
Howard Hughes' 1931 movie Platinum Blonde starring Jean Harlow is noted to have popularized platinum blonde hair color in the US. After the movie's success Hughes's team established a chain of "Platinum Blonde clubs" in several cities and offered a $10,000 prize that would go to any hairdresser who could copy Harlow's shade. [9] Though Harlow denied her hair was bleached, [10] the platinum blonde color was reportedly achieved with a weekly application of ammonia, Clorox bleach, and Lux soap flakes. This process weakened and damaged Harlow's naturally ash-blonde hair. [11]
During the 1930s Lawrence M. Gelb advanced the formulas of the bleaching products. In 1950, Clairol, the company Gelb founded with wife Jane Clair, introduced the first one-step hair dye product that lightened hair, which became a huge success with the masses. [9]
Melanin pigments, which give hair a darker color, can be broken down with oxidation. [12] Most commercial bleaching formulas contain hydrogen peroxide and persulfate salts, which under alkaline conditions created by ammonia or monoethanolamine can bleach the hair. Persulfate salts, in combination with hydrogen peroxide or alone, are known for their ability to degrade organics after activation with heat, transition metals, ultraviolet light, or other means that produce the sulfate radical. Without activation, the persulfate anion is known to react with some organic chemicals, although with slow kinetics. [13] When melanin is oxidized, oxygen gas is released. [12] Products for bleaching one's hair at home usually contain a 6% solution of hydrogen peroxide, while products for use in a hair salon can contain up to 9%. [12] Hair bleaching products can damage hair and cause severe burns to the scalp when applied incorrectly or left on too long. [14]
Industrial bleaches that work by reduction (such as sodium hydrosulphite) react with a chromophore, the part of the molecule responsible for its color and decrease the number of carbon-oxygen bonds in it, making it uncoloured. This process might be reversed to a certain extent by oxygen in the air, such as yellowing of bleached paper if left uncovered. In contrast, hydrogen peroxide chemically alters the chromophore by increasing the number of carbon-oxygen bonds. Due to the relative absence of reducing agents in the environment, chromophores cannot restore themselves as seen in reduction-based bleaches. [15]
Bleaching the hair is a gradual process and different colors may be achieved dependent on the original hair color, application time, and strength of the product used. Applied on black hair, the hair will change its color to brown, red, orange, orange-yellow, yellow, and finally pale yellow. [16]
Toning is a common practice after bleaching to mask the undesirable red and orange tones of "brassy" hair using a toner dye. Through toning, the yellow hue of fully bleached hair can be removed to achieve platinum blond hair. The appropriate color of the toner depends on the color of the bleached hair; e.g. to remove the yellow tones a violet toner dye will be needed, but to neutralize red and orange hues a green and blue toner would be more suitable. Tinted shampoos can also be used to tone hair. [16] [17]
Excessive exposure to the sun is the most common cause of structural damage of the hair shaft. Photochemical hair damage encompasses hair protein degradation and loss, as well as hair pigment deterioration [18] Photobleaching is common among people with European ancestry. Around 72 percent of customers who agreed to be involved in a study and have European ancestry reported in a recent 23andMe research that the sun lightens their hair. The company also have identified 48 genetic markers that may influence hair photobleaching. [19]
Drug testing methods using hair samples are found to be disrupted by chemical hair treatments including bleaching. According to a 2019 study bleaching has caused strong chemical degradation on cannabinoids in hair, while permanent colorings in single applications had only negligible effects on cannabinoids. [20] A 2021 study found similar results for methamphetamine concentrations in hair. [21]
Persulfate containing products may produce a variety of cutaneous and respiratory responses, such as allergic eczematous contact dermatitis, irritant dermatitis, localized edema, generalized urticaria, rhinitis, asthma, dizziness, and syncope. [22]
Hydrogen peroxide is a chemical compound with the formula H2O2. In its pure form, it is a very pale blue liquid that is slightly more viscous than water. It is used as an oxidizer, bleaching agent, and antiseptic, usually as a dilute solution in water for consumer use, and in higher concentrations for industrial use. Concentrated hydrogen peroxide, or "high-test peroxide", decomposes explosively when heated and has been used both as a monopropellant and an oxidizer in rocketry.
Human hair color is the pigmentation of human hair follicles due to two types of melanin: eumelanin and pheomelanin. Generally, if more melanin is present, the color of the hair is darker; if less melanin is present, the hair is lighter. The tone of the hair is dependent on the ratio of black or brown eumelanin to yellow or red pheomelanin. Levels of melanin can vary over time causing a person's hair color to change, and it is possible to have hair follicles of more than one color on the same person. Some hair colors are associated with some ethnic groups due to observed higher frequency of particular hair color within their geographical region, e.g. straight dark hair amongst East Asians, Southeast Asians, Polynesians and Native Americans, a large variety of dark, fair, curly, straight, wavy and bushy hair amongst Europeans, West Asians and North Africans, curly, dark, and uniquely helical hair with Sub Saharan Africans, whilst gray, white or "silver" hair is often associated with age and wisdom.
Hair coloring, or hair dyeing, is the practice of changing the hair color. The main reasons for this are cosmetic: to cover gray or white hair, to alter hair to create a specific look, to change a colour to suit preference or to restore the original hair color after it has been discolored by hairdressing processes or sun bleaching.
Blond or blonde, also referred to as fair hair, is a human hair color characterized by low levels of the dark pigment eumelanin. The resultant visible hue depends on various factors, but always has some yellowish color. The color can be from the very pale blond to reddish "strawberry" blond or golden-brownish ("sandy") blond colors. Occasionally, the state of being blond, and specifically the occurrence of blond traits in a predominantly dark or colored population are referred to as blondism.
Benzoyl peroxide is a chemical compound (specifically, an organic peroxide) with structural formula (C6H5−C(=O)O−)2, often abbreviated as (BzO)2. In terms of its structure, the molecule can be described as two benzoyl (C6H5−C(=O)−, Bz) groups connected by a peroxide (−O−O−). It is a white granular solid with a faint odour of benzaldehyde, poorly soluble in water but soluble in acetone, ethanol, and many other organic solvents. Benzoyl peroxide is an oxidizer, but it is principally used as in the production of polymers.
In chemistry, hypochlorite, or chloroxide is an anion with the chemical formula ClO−. It combines with a number of cations to form hypochlorite salts. Common examples include sodium hypochlorite and calcium hypochlorite. The Cl-O distance in ClO− is 1.69 Å.
Blonde stereotypes are stereotypes of blonde-haired people. Sub-types of this stereotype include the "blonde bombshell" and the "dumb blonde". Blondes are stereotyped as more desirable, but less intelligent than brunettes. There are many blonde jokes made on these premises.
Tooth whitening or tooth bleaching is the process of lightening the color of human teeth. Whitening is often desirable when teeth become yellowed over time for a number of reasons, and can be achieved by changing the intrinsic or extrinsic color of the tooth enamel. The chemical degradation of the chromogens within or on the tooth is termed as bleaching.
Hydroquinone, also known as benzene-1,4-diol or quinol, is an aromatic organic compound that is a type of phenol, a derivative of benzene, having the chemical formula C6H4(OH)2. It has two hydroxyl groups bonded to a benzene ring in a para position. It is a white granular solid. Substituted derivatives of this parent compound are also referred to as hydroquinones. The name "hydroquinone" was coined by Friedrich Wöhler in 1843.
Lead(II) acetate, also known as lead acetate, lead diacetate, plumbous acetate, sugar of lead, lead sugar, salt of Saturn, or Goulard's powder, is a white crystalline chemical compound with a slightly sweet taste. Its chemical formula is usually expressed as Pb(CH3COO)2 or Pb(OAc)2, where Ac represents the acetyl group. Like many other lead compounds, it is toxic. Lead acetate is soluble in water and glycerin. With water it forms the trihydrate, Pb(OAc)2·3H2O, a colourless or white efflorescent monoclinic crystalline substance.
Sodium persulfate is the inorganic compound with the formula Na2S2O8. It is the sodium salt of peroxydisulfuric acid, H2S2O8, an oxidizing agent. It is a white solid that dissolves in water. It is almost non-hygroscopic and has good shelf-life.
Hair dye stripping is a process used to rid the hair of unwanted deposited color.
The textile bleaching is one of the steps in the textile manufacturing process. The objective of bleaching is to remove the natural color for the following steps such as dyeing or printing or to achieve full white. All raw textile materials, when they are in natural form, are known as 'greige' material. They have their natural color, odor and impurities that are not suited to clothing materials. Not only the natural impurities will remain in the greige material, but also the add-ons that were made during its cultivation, growth and manufacture in the form of pesticides, fungicides, worm killers, sizes, lubricants, etc. The removal of these natural coloring matters and add-ons during the previous state of manufacturing is called scouring and bleaching.
Sodium nonanoyloxybenzenesulfonate (NOBS) is an important component of laundry detergents and bleaches. It is known as a bleach activator for active oxygen sources, allowing formulas containing hydrogen peroxide releasing chemicals to effect bleaching at lower temperatures.
Hair highlighting/lowlighting is changing a person's hair color, using lightener or haircolor to lift the level or brightness of hair strands. There are four basic types of highlights: foil highlights, hair painting, frosting, and chunking. Highlights can be any color, as long as it is a lighter level than the surrounding hair. Hair lightened with bleach or permanent color will be permanent until new growth begins to show. Highlighted hair can make the hair appear fuller. Therefore, it is sometimes recommended for people with thin and fine hair. It also a recommended service for achieving better color balance with people that have at least 50% gray, and it also helps to diminish the line of demarcation once the new growth is showing from permanent hair color.
Bleach is the generic name for any chemical product that is used industrially or domestically to remove colour (whitening) from fabric or fiber or to clean or to remove stains in a process called bleaching. It often refers specifically to a dilute solution of sodium hypochlorite, also called "liquid bleach".
Bleaching of wood pulp is the chemical processing of wood pulp to lighten its color and whiten the pulp. The primary product of wood pulp is paper, for which whiteness is an important characteristic. These processes and chemistry are also applicable to the bleaching of non-wood pulps, such as those made from bamboo or kenaf.
Hot roots is a term used by hair stylists to describe the condition when, after applying an artificial pigment to the hair, the roots are noticeably ‘warmer’ in color than the lengths and ends of the hair. This can happen for a few reasons, but the two most likely causes are explained below. It is helpful to understand the process of lightening, or "lifting", the natural hair color. The color of natural hair is determined by the melanin present. Generally, the more melanin, the darker the hair. In order to lighten the color of hair, a chemical must penetrate the cuticle of the hair, enter the cortex and destroy the melanin. Permanent hair color, bleach and other decolorants can do this to varying degrees. Permanent hair color, unlike bleach and other decolorants, leaves behind an artificial pigment while destroying the natural pigment. This pigment is a mix of the primary colors: blue, red and yellow. The chemical reaction that occurs within the hair follicle during a color-lightening process, in essence, destroys the natural melanin as well as the blue, red and yellow hues, respectively, one at a time. The extent to which this occurs can be affected by the proportion of chemicals present, especially hydrogen peroxide, as well as by the temperature at which the hair is kept during the process. Artificial hair pigment, unlike natural hair pigment, cannot be lightened to a noticeable extent by other artificial hair color.
Lightfastness is a property of a colourant such as dye or pigment that describes its resistance to fading when exposed to light. Dyes and pigments are used for example for dyeing of fabrics, plastics or other materials and manufacturing paints or printing inks.